Imaginary Gauge-steerable Edge Modes In Non-Hermitian Aubry-André-Harper Model

Fuente: arXiv
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Main Authors: Miao, Yazhuang, Ding, Wei, Wang, Litong, Zhao, Xiaolong, Liu, Shengguang, Yi, Xuexi
Format: Preprint
Published: 2026
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_version_ 1866908774941327360
author Miao, Yazhuang
Ding, Wei
Wang, Litong
Zhao, Xiaolong
Liu, Shengguang
Yi, Xuexi
author_facet Miao, Yazhuang
Ding, Wei
Wang, Litong
Zhao, Xiaolong
Liu, Shengguang
Yi, Xuexi
contents We identify steerable exponentially localized in-gap mode in a quasiperiodic non-Hermitian Aubry-André-Harper chain with a spatially fluctuating, zero-mean imaginary gauge field. Under open boundary conditions, the system is exactly related to the Hermitian AAH model by a nonunitary gauge transformation: the OBC spectrum and Lyapunov exponents are unchanged, while eigenstates acquire a gauge-dependent envelope. In a parameter region with spectrally isolated in-gap boundary modes, we find two exponentially localized in-gap modes with sharply different responses to the imaginary gauge field. One remains boundary pinned, but the other is gauge-steerable: it stays exponentially localized while its probability maximum shifts as the gauge field is changed, with its eigenenergy unchanged. We further show that weak on-site gain, applied at a single site chosen once and then kept fixed, can dynamically prepare this steerable mode from a generic bulk wave packet. Changing the gauge field then yields exponentially localized states at different locations.
format Preprint
id arxiv_https___arxiv_org_abs_2601_06746
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Imaginary Gauge-steerable Edge Modes In Non-Hermitian Aubry-André-Harper Model
Miao, Yazhuang
Ding, Wei
Wang, Litong
Zhao, Xiaolong
Liu, Shengguang
Yi, Xuexi
Optics
Disordered Systems and Neural Networks
We identify steerable exponentially localized in-gap mode in a quasiperiodic non-Hermitian Aubry-André-Harper chain with a spatially fluctuating, zero-mean imaginary gauge field. Under open boundary conditions, the system is exactly related to the Hermitian AAH model by a nonunitary gauge transformation: the OBC spectrum and Lyapunov exponents are unchanged, while eigenstates acquire a gauge-dependent envelope. In a parameter region with spectrally isolated in-gap boundary modes, we find two exponentially localized in-gap modes with sharply different responses to the imaginary gauge field. One remains boundary pinned, but the other is gauge-steerable: it stays exponentially localized while its probability maximum shifts as the gauge field is changed, with its eigenenergy unchanged. We further show that weak on-site gain, applied at a single site chosen once and then kept fixed, can dynamically prepare this steerable mode from a generic bulk wave packet. Changing the gauge field then yields exponentially localized states at different locations.
title Imaginary Gauge-steerable Edge Modes In Non-Hermitian Aubry-André-Harper Model
topic Optics
Disordered Systems and Neural Networks
url https://arxiv.org/abs/2601.06746